16420581 has 12 divisors (see below), whose sum is σ = 23755680. Its totient is φ = 10929960.

The previous prime is 16420577. The next prime is 16420601. The reversal of 16420581 is 18502461.

16420581 is a `hidden beast` number, since 1 + 64 + 20 + 581 = 666.

It is not a de Polignac number, because 16420581 - 2² = 16420577 is a prime.

It is a super-2 number, since 2×16420581² = 539270960755122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16420081) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7800 + ... + 9678.

It is an arithmetic number, because the mean of its divisors is an integer number (1979640).

Almost surely, 2^16420581 is an apocalyptic number.

It is an amenable number.

16420581 is a deficient number, since it is larger than the sum of its proper divisors (7335099).

16420581 is a wasteful number, since it uses less digits than its factorization.

16420581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2856 (or 2853 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 16420581 is about 4052.2316073986. The cubic root of 16420581 is about 254.1730535825.

The spelling of 16420581 in words is "sixteen million, four hundred twenty thousand, five hundred eighty-one".